| Niagara Falls to Karlovo | 4,868.27 mi (7,834.72 km) |
| Niagara Falls to Karnobat | 4,951.26 mi (7,968.28 km) |
| Niagara Falls to Kavarna | 4,964.10 mi (7,988.94 km) |
| Niagara Falls to Kazanlak | 4,892.12 mi (7,873.11 km) |
| Niagara Falls to Knezha | 4,801.91 mi (7,727.93 km) |
| Niagara Falls to Kostinbrod | 4,799.33 mi (7,723.77 km) |
| Niagara Falls to Kozloduy | 4,775.90 mi (7,686.06 km) |
| Niagara Falls to Kyustendil | 4,802.45 mi (7,728.80 km) |
| Niagara Falls to Levski | 4,847.77 mi (7,801.74 km) |
| Niagara Falls to Lom | 4,755.13 mi (7,652.64 km) |
| Niagara Falls to Lovech | 4,842.53 mi (7,793.30 km) |
| Niagara Falls to Lukovit | 4,818.60 mi (7,754.78 km) |
| Niagara Falls to Lyaskovets | 4,881.99 mi (7,856.81 km) |
| Niagara Falls to Mezdra | 4,802.99 mi (7,729.67 km) |
| Niagara Falls to Momchilgrad | 4,942.51 mi (7,954.19 km) |
